Jurgen Klopp's side had to make the 293-mile trip to Home Park after they were held to a frustrating goalless draw in the initial meeting between the two at Anfield.

However, Lucas ensured the long journey was not a wasted one when he headed home Philippe Coutinho's corner early in the first half.

The win should have been more comfortable for the Reds but Divock Origi's poor penalty was comfortably saved by home keeper Luke McCormick.

Plymouth, who are 66 places below Liverpool in the football pyramid, were not overawed by their Premier League opponents and came closest to equalising when Jake Jervis hit the post with a scissor kick midway through the second half.

Liverpool's reward for victory is a home tie against Championship side Wolverhampton Wanderers on 28 January.